Copper bioaccumulation and hepatoprotein synthesis during acclimation to copper by juvenile rainbow trout

Abstract

Rainbow trout were exposed for 3 wk to copper at 0.09, 0.18, 0.29, 0.40, or 0.59 of the mean control incipient lethal level (ILL) of copper. Whole body copper concentration increased with both exposure concentration and time. Mean residues stabilized in the range of 34 to 37 μg/g dry weight after 2 to 3 wk of exposure at 0.29 to 0.59 ILL. After 3 wk at 0.29 ILL of copper, most fish survived a subsequent exposure at 1.7 ILL, during which their elevated body concentration of copper did not change appreciably (35 to 33 μg/g). In contrast, control fish died rapidly, their body concentration rising from 3.8 to 7.4 μg/g). Sublethal copper exposure increased the protein content of a low-molecular-weight hepatoprotein fraction. There was also greater incorporation into that protein of 14C from intraperitoneally administered [ 14C]leucine. Fish exposed to cadmium showed a similar increase in hepatoprotein but not increased 14C incorporation. This suggests different, metal-specific proteins. Results are discussed with respect to a previously reported acclimation to copper by the fish, acclimation which significantly altered lethal tolerance of copper.